The present invention relates to a method for providing an operator of a work machine with operating instructions.
The term “work machine” comprises different types of material handling vehicles like construction machines, such as a wheel loader and a dump truck (such as an articulated hauler). A work machine is provided with a bucket, container or other type of work implement for carrying/transporting a load. Further terms frequently used for work machines are “earth-moving machinery”, “off-road work machines” and “construction equipment”.
In connection with transportation of heavy loads, e.g. in contracting work, work machines are frequently used. A work machine may be operated with large and heavy loads in areas where there are no roads, for example for transports in connection with road or tunnel building, sand pits, mines and similar environments.
A work machine is often used in a repeated work cycle. The term “work cycle” comprises a route of the work machine (ie the work cycle travel path) and a movement of a work implement, such as a bucket, (lifting/lowering operation). Thus, the travel path defines a movement of the work machine between two destinations at a distance from each other. The work cycle is repeated in the same geographical area. During the performance of the work cycle, the work machine often encounters different gradients of the ground (uphill and downhill), ground conditions and turns (cornering).
According to a first work cycle example, a wheel loader typically drives into a heap of material, lifts the bucket, reverses out of the heap, turns and is forwarded towards a dump truck where it unloads the material onto the container of the dump truck. After unloading, the wheel loader returns to the starting position.
A second work cycle example for a wheel loader is the so called “load & carry cycle” with a small ramp at the end. According to this example, material is collected in the bucket, the wheel loader is reversed, turned and forwarded a longer distance (100-400 meters) to a crusher or conveyor belt, which is located on top of the ramp, and the bucket is emptied. The wheel loader is thereafter driven back again.
According to a third work cycle example, a dump truck is loaded at a first position, driven along a varied route, unloaded at a second position and driven back along the varied route. Normally, an excavator or wheel loader loads the container of the dump truck at the first position.
The invention will be described below for a wheel loader. This should be regarded as a non-limiting example of a work machine. The wheel loader comprises a powertrain for propelling the machine via the wheels. A power source, such as an internal combustion engine, and especially a diesel engine, is adapted to provide the power for propelling the wheel loader. The wheel loader further comprises a hydraulic system for performing certain work functions, such as lifting and tilting a work implement and steering the machine. The power source is also adapted to provide the power for controlling the hydraulic work functions. More specifically, one or more hydraulic pumps are driven by the power source in order to provide hydraulic actuators (such as hydraulic cylinders) with pressurized hydraulic fluid.
It is desirable to achieve a method which creates conditions for an improved operation of a work machine operating in a repeated work cycle.
According to an aspect of the present invention, a method is provided for providing an operator of a work machine with operating instructions when the work machine is used in a repeated work cycle, comprising the step of automatically instructing the operator of the work machine how to operate the work machine in an optimum way with regard to a specific parameter on the basis of characteristics of the specific work cycle.
According to a first preferred example, the specific parameter regards vibrations affecting the operator in operation, such as WBV (Whole Body Vibrations).
According to a second preferred example, the specific parameter regards energy consumption (for example fuel consumption).
Preferably, the operation instructions or guidance are presented to the operator in an operator compartment of the vehicle when the operator is in an operational position. Thus, the operator is seated when the instructions are presented to him. In other words, there is an educational interface in the cab. The instruction preferably comprises visual information displayed to the operator. The display means may comprise a separate screen in the instrument panel of the vehicle and/or a head-up display, wherein a virtual image is projected from the instrument panel onto the windscreen. Further, the instruction may comprise audio information, which may be presented via an automated voice.
A suitable time is preferably selected for presenting the instructions to the operator in a safe way. With regard to an articulated hauler, the instructions may be presented during a loading operation. Alternatively, the instructions are presented to the operator shortly before reaching a specific occurrence when performing the work cycle.
The work cycle characteristics may regard a work machine internal characteristic, such as a work machine behaviour or operator behaviour, and/or an external characteristic, such as geographical properties of the work cycle travel path (terrain characteristics). More specifically, the characteristics may comprise a predicted and/or experienced sequence of events (occurrences) that takes place during performance of the work cycle and which is relevant for the control of the work machine.
Therefore, according to a preferred embodiment, the method comprises the step of informing the operator of occurrences along a travel path of the work cycle, which occurrences have an impact on operation of the work machine in an optimum way with regard to said specific parameter, and instructing the operator how to operate the work machine past the positions of the occurrences. For example, the instructions may comprise a favourable route past the occurrence and/or operating instructions with regard to braking and/or acceleration and/or steering.
The occurrences are of such a magnitude that they are relevant for the control of the work machine. Each such occurrence is preferably associated to a position along the work cycle travel path.
According to a preferred embodiment, the operator instruction is based on a change in the ground, such as ground conditions, for example any unevenness in the ground, like a pit or stone. According to the example of vibrations affecting the operator, the operator is preferably instructed of the position of the unevenness and also recommended to drive the work machine around the unevenness.
According to a further preferred embodiment, the operator instruction is based on a change in a work cycle travel path. Preferably, operator instruction is based on a change of direction of a work cycle travel path in a horizontal plane and/or on a change of ground inclination of a work cycle travel path. According to the example of fuel consumption, the operator may be instructed of the position of the work cycle travel path and also recommended an advantageous gear sequence and/or gas pedal operation and/or brake operation past the work cycle travel path change.
Thus, knowledge of the work cycle creates conditions for reliably predicting forthcoming events (occurrences) in the work cycle and instructing the operator correspondingly for operating the work machine in an efficient way. Such work cycle knowledge may be achieved either from a previously performed lap of the specific work cycle and/or from pre-available information of the work cycle, such as topographical maps.
Preferably, the method comprises the step of repeatedly detecting at least one machine operational parameter during performing a work cycle lap, such as in the hydraulic system and/or the drive train.
Thus, an event may be established on the basis of the detected operational parameter in a previously performed work cycle lap and used for instructing an operator of a work machine how to operate it in a later performed work cycle. More particularly, an individual operator may learn from past experiences. For example, driving patterns with regard to steering wheel deflection, gas pedal operation, brake pedal operation, work implement operation etc are recognized and stored. Further, operational characteristics recorded from one work machine may be distributed to other participants in a fleet operating the specific work cycle.
According to an alternative, or complementary embodiment, the method comprises the step of receiving pre-available information of the work cycle in question.
Such information may be formed by geographical maps of the area covering the work cycle travel path, knowledge of the specific work cycle travel path (comprising curves, ascending sections and descending sections), the material to be transported, ground conditions, weather conditions etc. For example, a global navigation satellite system (GNSS) (such as the GPS) may be used for establishing the work cycle travel path.
According to one example, the operator instruction is established on the basis of both detected operational parameters while performing the work cycle and available information of the work cycle in question. Thus, the work cycle route may be produced in a topographical map, wherein turns and slopes are defined. The operator instruction is based on such a topographical map and it may be modified based on detected operational conditions. Thus, the map may be continuously updated depending on the current state of the travel path. In this way, the instructions may be quickly updated depending on different days, time of the day etc.
According to a further preferred embodiment, the method comprises the step of predicting an effect of the characteristics of the specific work cycle on the specific parameter and instructing the operator in response to the predicted effect. The instructions may comprise information regarding which type of characteristics (such as a bumpiness level) that is identified. The instructions may further comprise an explanation of the reason why the characteristics has a negative impact on the specific parameter. The instructions may further comprise concrete advice how to operate the work machine in an optimum way past a portion of a travel path of the work cycle, which is associated to the specific characteristics. The concrete advice may comprise advice to slow down the work machine and/or to alter the course of the work machine. In this way, the instruction does not only serve to be informational, but also educational.
According to a further preferred embodiment, the method comprises the step of instructing the operator of the predicted effect on the specific parameter along a travel path of the work cycle ahead of the work machine. The operator is preferably instructed of the predicted effect on the specific parameter (such as vibrations) just before entering a travel path portion with said characteristics. In this way, the operator is informed at an advantageous point in time (just before the specific travel path portion with said characteristics) in order to handle the machine efficiently.
It is also desirable to achieve a method which creates conditions for an improved operation of a work machine.
Other advantageous features and functions of various embodiments of the invention are set forth in the following description.